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利用Li-840红外气体分析仪和Li-6400-09土壤呼吸气室组装而成的动态密闭土壤呼吸测定系统,于2006年生长季对内蒙古库布齐沙漠油蒿(Artemisia ordosica)生态系统2种不同类型土壤的土壤呼吸速率进行了野外测定,分析了日动态、季节动态及其对环境因子的响应,并阐述了油蒿灌丛空间异质性的特征.结果表明,油蒿灌丛的土壤呼吸速率日动态呈单峰曲线,在12:00左右有最大值.在适宜的水分和温度条件下,生长季里土壤呼吸速率在7~8月份出现最大值.土壤呼吸速率的季节动态与土壤含水量有显著的相关关系,表明水分是限制生长季干旱区灌丛土壤呼吸的最重要因子,分别可以解释油蒿冠幅下土壤和裸地的土壤呼吸速率2006年主要生长季节(5~9月)变化的75%和77%.油蒿灌丛土壤呼吸速率在空间尺度上存在着显著的异质性.油蒿冠幅覆盖下的土壤呼吸速率季节平均值为(155.58±15.20)mg.(m2.h)-1,要显著地大于灌丛间裸地的数值(110.50±6.77)mg.(m2.h)-1.2种不同类型土壤的土壤呼吸速率是由于根生物量的差异引起的,根生物量可以解释2006年生长季库布齐油蒿灌丛土壤呼吸速率空间异质性的43%.结果表明,在植被覆盖度异质性较大的灌丛生态系统中,要准确定量生态系统碳的释放时,必须充分考虑小尺度上土壤呼吸的空间异质性.
A dynamic confined soil respiration measuring system assembled with Li-840 infrared gas analyzer and Li-6400-09 soil respiration gas chamber was used to monitor the growth of Artemisia ordosica ecosystem in the Kubuqi Desert in Inner Mongolia in 2006 The soil respiration rate of different types of soils was measured in the field, the daily dynamics, seasonal dynamics and their responses to environmental factors were analyzed, and the characteristics of spatial heterogeneity of Artemisia ordosica shrubs were described. The results showed that the soil of Artemisia ordosica The daily dynamic of respiration rate showed a single peak curve and had the maximum at about 12:00. Under suitable water and temperature conditions, the soil respiration rate in the growing season peaked from July to August. The seasonal dynamics of soil respiration rate and soil Water content was significantly correlated, indicating that water is the most important factor limiting the respiration of soil in shrubs in the arid zone of growing season, which can explain the soil respiration rate of soil and bare land under the crown of Artemisia ordosica respectively. The main growth season in 2006 (5 ~ 9 Month and 75% and 77%, respectively.The seasonal variation of soil respiration rate in Artemisia ordosica shrubs was significant at the spatial scale.The season average soil respiration rate was (155.58 ± 15.20) mg. (m 2.h) -1, which was significantly higher than that of the bare land (110.50 ± 6.77) mg. (M2.h) -1. The soil respiration rate of the two different types of soils was due to the difference in root biomass, The root biomass could account for 43% of the spatial heterogeneity of soil respiration rate in the shrubs of Artemisia ordosica in the growing season in 2006. The results showed that in the shrub ecosystem with large vegetation coverage heterogeneity, When system carbon is released, the spatial heterogeneity of soil respiration at the small scale must be fully taken into account.